Investigation of a Portable Performance Measurement System for Neurologic Screening in Clinics

Motivated by the need for clinical screening for early detection of neurologic disease, a prototype portable instrument dubbed the Human Performance MultiMeter (HPMM) was developed. The HPMM is based on a set of lab- based performance capacity tests developed and evaluated over the last two decades. We attempted to integrate selected functionality of a set of modular lab-based instruments into a single, small package. In the present study, a 4 th generation prototype was developed and evaluated for usability, measurement repeatability, and preliminary measurement validity. Five performance capacity tests (upper extremity coordination, isometric grip strength, simple response speed, rapid alternating movement, and steadiness/tremor) were administered to twenty healthy adult volunteers. Short-term reliability was investigated using a test-retest protocol. Most measures were found to possess good test-retest reliability (r>0.75). Preliminary validity was investigated by comparing results to those obtained with non-portable devices that served as models for the HPMM. Results were in good agreement with those instruments. It is concluded that measures of good fidelity can be obtained with this type of instrument. I. INTRODUCTION There has been growing interest in early detection of neurologic diseases such as Parkinson's Disease and Alzheimer's Disease. While relatively low-cost screening tools suitable for widespread use exist for cardiovascular and other systems, the method currently in widespread use for neurologic screening is largely based on subjective observation and lacks sensitivity. This has motivated the use of more objective and quantitative performance tests (1)-(3). Set-ups to do such performance tests generally require a separate lab room and the instruments would not be considered to be portable. To access the widest population base, we envision a small device that could be part of general practitioner's office and perhaps be used by a nurse or physician's assistant during routine check-ups or as an initial follow-up to patient reported concerns. Given this context, a prototype portable instrument dubbed the Human Performance MultiMeter (HPMM) was developed. The tests performed with the HPMM are based on a set of lab-based performance capacity tests (3) developed and evaluated over the last two decades. Analogy is made to a Digital MultiMeter (DMM), which can perform a basic set of generic measurements (e.g., voltage, resistance, etc.). Similarly, when used in a stand-alone mode (other modes incorporated in the design are not described here), the HPMM could be used to measure generic quantities such as force, speed, etc. Coupled with predefined procedures, specific measurements could be obtained that would represent strength of different muscle groups (from force), speed of movement about specific joints (from speed measurements), etc. The HPMM thus attempts to leverage advancements in sensor, microcontroller, and low-power instrumentation technology to integrate selected, proven aspects of measurement functionality from our modular lab- based instruments (3) into a small, easy-to-use package. In the present study, a 4 th generation prototype was developed and evaluated (4) for usability, measurement repeatability, and preliminary measurement validity. The HPMM was designed as a flexible hardware platform that could support the implementation of currently envisioned as well as future performance capacity measurements. The 4 th